Cambridge A Level Marine Science 9693 — 2018 Oct/Nov Paper 2 · Variant 0

1 The cold-water coral species, Lophelia pertusa, lives at depths of between 39 m and 3000 m. (a) Many species of coral are coloured, but L. pertusa is white. With reference to the information provided, suggest why L. pertusa is white. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [3] (b) Scientists carried out an investigation into the effect of rate of flow of water on food capture by L. pertusa. The apparatus used is shown in Fig. 1.1. variable speed motor to change lid water flow rate 0.3 m chamber containing sea water propeller 0.15 m Fig. 1.1 Specimens of L. pertusa were placed into the chamber and left to settle for one hour. A known mass of zooplankton was then added to the chamber and a water flow rate set. The mass of zooplankton removed by the coral per hour was measured. This was recorded as the capture rate. This was repeated at different flow rates. The experiment was then repeated using phytoplankton instead of zooplankton. The results are shown in Table 1.1. Table 1.1 capture rate capture rateflow rate / mg zooplankton removed per hour / mg phytoplankton removed per hour slow 24 21 medium 19 63 fast 11 0 (i) Suggest two properties of the sea water that need to be kept constant in this experiment. 1 ........................................................................................................................................ 2 ........................................................................................................................................ [2] (ii) On the grid below, draw a bar chart to show the results from Table 1.1. [4] (iii) Write a hypothesis based on the results of this investigation. ........................................................................................................................................... ...................................................................................................................................... [1] (iv) Predict the flow rate at which this species of coral would grow fastest. ................................................................ Give a reason for your answer. ........................................................................................................................................... ...................................................................................................................................... [1] [Total: 11]

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2 Fig. 2.1 shows a settlement of acorn barnacles, Semibalanus balanoides, on a rocky shore. 1 cm Fig. 2.1 A student decided to look at the distribution of three different barnacle species on a rocky shore. The results of this investigation are shown in Table 2.1. Table 2.1 distance above number of barnacles per unit area low water spring tide line / m species 1 species 2 species 3 0 0 98 13 2 1 42 49 4 6 3 87 6 49 0 63 8 91 0 15 10 84 0 5 (a) Describe an experimental procedure the student could use to carry out this investigation. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [4] (b) Use the data in Table 2.1 to determine where the greatest biodiversity of barnacles is found. ............................................................ m [1] (c) Use the data in Table 2.1 to compare the distribution of the three barnacle species. Suggest reasons for the differences in distribution. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [4] [Total: 9]

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3 (a) Some coral reefs form atolls. Explain the Darwin-Dana-Daly theory of atoll formation. You may include diagrams to aid your explanation. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [6] (b) Discuss the factors that can lead to a transition from coral reef growth to coral reef erosion. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [6] (c) Explain how coral reefs help to protect shores from the effects of storm surges. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [3] [Total: 15]

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4 (a) Hydrothermal vent communities are areas of higher productivity than the surrounding areas. (i) State the meaning of the term community. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] (ii) Describe how hydrothermal vents are formed. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [5] (b) At hydrothermal vents, there is a mutualistic relationship between hydrothermal vent bacteria and tubeworms. Tropical coral polyps and zooxanthellae also have a mutualistic relationship. Discuss the similarities and differences between these two relationships. similarities ................................................................................................................................. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... differences ................................................................................................................................ ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... [8] [Total: 15]

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